Warfare in Crusader Kings III is a multifaceted endeavor, extending far beyond simply raising armies and marching them into enemy territory. Success hinges on strategic planning, economic backing, and understanding the nuances of your military forces. Your primary military units are raised from your levies, which are a percentage of your controlled population's fighting strength. These are supplemented by Men-at-Arms (MaA), professional soldiers who provide significant combat bonuses and are crucial for overcoming superior numbers or specialized enemy units. Each type of MaA, such as Archers, Heavy Infantry, or Knights, excels in different terrain and against specific enemy types. For instance, Archers are potent in open terrain but vulnerable to cavalry charges.
Raising Armies
To raise an army, navigate to your realm's military tab. You can select individual levies and MaA regiments to form your armies. It's vital to keep your MaA at full strength by spending gold to reinforce them. Consider the composition of your army; a balanced force with infantry, archers, and cavalry, along with specialized units like siege weapons, will be more effective. Remember that maintaining large armies incurs significant upkeep costs, so ensure your treasury can support them.
Declaring War & Casus Belli
War is initiated through a Casus Belli (cause for war). These can be obtained through various means, such as fabricating claims, holy wars, or specific event chains. Each Casus Belli has a target war goal, such as conquering a specific county or gaining independence. The stronger your Casus Belli, the higher your War Score will be if you achieve your objectives.
Combat & Sieges
Once armies clash, combat is resolved based on several factors, including troop quality, commander's martial skill, terrain, and the presence of advantages like flanking or defensive bonuses. Sieges are a separate but equally important aspect of warfare. To capture a province, you must besiege its holding. Siege weapons significantly speed up this process. Successfully besieging a province contributes to your War Score, and capturing the enemy's war goal county is often the quickest way to win a war.
Naval Power
For island realms or those engaging in overseas conflicts, naval power is essential. Ships transport your armies and can blockade enemy ports, preventing reinforcements and damaging their economy. Building and maintaining a fleet requires significant investment but is indispensable for projecting power across water.